1. Field of the Invention
The present invention relates to an apparatus for producing embroidery data to control a sewing machine to form an embroidery on a work sheet.
2. Related Art Statement
There is known an embroidery sewing machine which automatically forms an embroidery on a work sheet such as a work cloth. Embroidery data are used to control the sewing machine to form the embroidery on the work sheet. The embroidery data include, e.g., sets of stitch-position data representative of stitch positions on the outline of a closed area to be filled with stitches to provide the embroidery, i.e., each stitch position corresponding to amounts of movement of the work sheet relative to the sewing needle in the X and Y directions pre-determined for the sewing machine. Embroidery data may otherwise include sets of block data representative of respective outlines of polygonal blocks as divisions of a closed area. U.S. Pat. No. 5,189,623 assigned to the Assignee of the present application discloses an embroidery data producing apparatus which automatically produces such embroidery data.
The above-identified embroidery data producing apparatus may be constituted by (a) a personal computer (PC), (b) an image scanner, (c) a keyboard, (d) a hard disk drive (HDD), and (e) a cathode ray tube (CRT) display. The elements (b) to (e) are connected to the PC. The conventional apparatus produces embroidery data based on a white-black original image, in the following manner:
First, the image scanner is operated to read in the original image from an original (e.g., black image drawn on a white sheet of paper), so that the PC produces image data representing the original image. Next, the PC produces one or more sets of outline data representative of the outline or outlines of one or more closed areas constituting the original image. Furthermore, the PC produces sets of block data representative of the outlines of an array of polygonal blocks such as quadrangles and/or triangles which extend in an embroidering direction, i.e., X and Y coordinates of the positions of the vertices of the quadrangular or triangular blocks, and it finally produces embroidery data, e.g., sets of stitch-position data representative of stitch positions located on the outline of each of the blocks where satin stitches or seed stitches, for example, are formed to fill the inside of each block.
There have been increasing demands for diversified and/or sophisticated embroideries. With this tendency, there have been provided embroidery sewing machines having improved performances, e.g., function of producing a multiple-color and/or elaborate embroidery. For even a home sewing machine, there have been demands to improve its performance so that the sewing machine has not only the function of forming an embroidery according to pre-stored embroidery data but also the function of forming an embroidery corresponding to an original image desired by an individual user.
For forming a multiple-color embroidery with different color threads, it is necessary to divide an original image into a plurality of "color-different" areas to be embroidered with the different color threads and produce a set of embroidery data for each of the color-different areas. However, the conventional embroidery data producing apparatus obtains only such image data representing the shape of an original image, e.g., "black" portions to be embroidered and "white" portions not to be embroidered. Thus, the embroidery data produced only represent which portion is to be embroidered and which portion is not to be embroidered.
The conventional apparatus requires an operator or user to divide a color original image into a plurality of color-different areas, prepare a plurality of secondary originals bearing the color-different areas, respectively, and produce a set of embroidery data for each of the color different areas from a corresponding one of the secondary originals. This work is very cumbersome and time-consuming. Additionally, in this method, the peripheral portions of the color-different areas may overlap each other, so that some portion may be embroidered with two or more different color threads and some portion may not be embroidered with any color threads.
Furthermore, if a color image scanner is used to obtain as image data a chromatic original image from an original and the image data obtained are plotted in the color space so as to divide the original image into a plurality of color-different areas and thereby produce a set of embroidery data for each of the color-different areas, a set of embroidery data is adversely prepared for the background area of the original image in the case where the color image is drawn on a white sheet of paper. Usually, however, the user does not wish to embroider the white background area.